The invention relates to sulfohydroxamic acid diarylamines and derivatives thereof. The disclosed diarylamines are pharmacologically active.
MEK enzymes are dual specificity kinases involved in, for example, immunomodulation, inflammation, and proliferative diseases such as cancer and restenosis.
Proliferative diseases are caused by a defect in the intracellular signaling system, or the signal transduction mechanism of certain proteins. Defects include a change either in the intrinsic activity or in the cellular concentration of one or more signaling proteins in the signaling cascade. The cell may produce a growth factor that binds to its own receptors, resulting in an autocrine loop, which continually stimulates proliferation. Mutations or overexpression of intracellular signaling proteins can lead to spurious mitogenic signals within the cell. Some of the most common mutations occur in genes encoding the protein known as Ras, a G-protein that is activated when bound to GTP, and inactivated when bound to GDP. The above-mentioned growth factor receptors, and many other mitogenic receptors, when activated, lead to Ras being converted from the GDP-bound state to the GTP-bound state. This signal is an absolute prerequisite for proliferation in most cell types. Defects in this signaling system, especially in the deactivation of the Ras-GTP complex, are common in cancers, and lead to the signaling cascade below Ras being chronically activated.
Activated Ras leads in turn to the activation of a cascade of serine/threonine kinases. One of the groups of kinases known to require an active Ras-GTP for its own activation is the Raf family. These in turn activate MEK (e.g., MEK1 and MEK2) which then activates MAP kinase, ERK (ERK, and ERK2). Activation of MAP kinase by mitogens appears to be essential for proliferation; constitutive activation of this kinase is sufficient to induce cellular transformation. Blockade of downstream Ras signaling, for example by use of a dominant negative Raf-1 protein, can completely inhibit mitogenesis, whether induced from cell surface receptors or from oncogenic Ras mutants. Although Ras is not itself a protein kinase, it participates in the activation of Raf and other kinases, most likely through a phosphorylation mechanism. Once activated, Raf and other kinases phosphorylate MEK on two closely adjacent serine residues, S218 and S222 in the case of MEK-1, which are the prerequisite for activation of MEK as a kinase. MEK in turn phosphorylates MAP kinase on both a tyrosine, y185 5, and a threonine residue, T183, separated by a single amino acid. This double phosphorylation activates MAP kinase at least 100-fold. Activated MAP kinase can then catalyze the phosphorylation of a large number of proteins, including several transcription factors and other kinases. Many of these MAP kinase phosphorylations are mitogenically activating for the target protein, such as a kinase, a transcription factor, or another cellular protein. In addition to Raf-1 and MEKK, other kinases activate MEK, and MEK itself appears to be a signal integrating kinase. Current understanding is that MEK is highly specific for the phosphorylation of MAP kinase. In fact, no substrate for MEK other than the MAP kinase, ERK, has been demonstrated to date and MEK does not phosphorylate peptides based on the MAP kinase phosphorylation sequence, or even phosphorylate denatured MAP kinase. MEK also appears to associate strongly with MAP kinase prior to phosphorylating it, suggesting that phosphorylation of MAP kinase by MEK may require a prior strong interaction between the two proteins. Both this requirement and the unusual specificity of MEK are suggestive that it may have enough difference in its mechanism of action to other protein kinases that selective inhibitors of MEK, possibly operating through allosteric mechanisms rather than through the usual blockade of the ATP binding site, may be found.
The invention features a compound having the formula (I) below: 
R1 is H, C1-8 alkyl, C3-8 alkenyl, C3-8 alkynyl, C3-8 cycloalkyl, phenyl, (phenyl)C1-4 alkyl, (phenyl)C3-4 alkenyl, (phenyl)C3-4 alkynyl, (C3-8 cycloalkyl) C1-4 alkyl, (C3-8 cycloalkyl)C3-4 alkenyl, (C3-8 cycloalkyl)C3-4 alkynyl, C3-8 heterocyclic radical, (C3-8 heterocyclic radical)C1-4 alkyl, (C3-8 heterocyclic radical)C3-4 alkenyl, (C3-8 heterocyclic radical)C3-4 alkynyl, (CH2)2-4 ORC or (CH2)2-4 NRRD. R2 is H, C1-4 alkyl, phenyl, C3-6 cycloalkyl, C3-6 heterocyclic radical, or (C3-6 cycloalkyl) methyl. Each of R3 and R4 is independently selected from H, F, NO2, Br and Cl. R5 is selected from H and F. R6 is H, F, Cl or CH3. Each of RC and RD is independently selected from H, C1-4 alkyl, C3-4 alkenyl, C3-4 alkynyl, C3-6 cycloalkyl, and phenyl; or NRCRD may be a piperidino, morpholino, or N-(C1-6 alkyl)piperazino ring. Each hydrocarbon radical above is optionally substituted with between 1 and 3 substituents independently selected from halo, hydroxyl, amino, (amino)sulfonyl, and NO2. Each heterocyclic radical above is optionally substituted with between 1 and 3 substituents independently selected from halo, C1-4 alkyl, C3-6 cycloalkyl, C3-4 alkenyl, C3-4 alkynyl, phenyl, hydroxyl, amino, (amino)sulfonyl, and NO2, wherein each substituent alkyl, cycloalkyl, alkenyl, alkynyl or phenyl is in turn optionally substituted with between 1 and 3 substituents independently selected from halo, C1-2 alkyl, hydroxyl, amino, and NO2. The invention also includes a pharmaceutically acceptable salt or C1-8 ester of a disclosed compound. For example, the disclosed alcohol compounds may form esters having the structure obtained by replacing the H of a hydroxyl group with a xe2x80x94C(xe2x95x90O)C1-7 acyl group.
The invention also relates to a pharmaceutical composition including (a) a compound of formula (I) and (b) a pharmaceutically-acceptable carrier.
The invention further relates to a method for treating proliferative diseases, such as cancer, restenosis, psoriasis, autoimmune disease, and atherosclerosis. Other aspects of the invention include methods for treating MEK-related (including ras-related) cancers, whether solid or hematopoietic. Examples of cancers include colorectal, cervical, breast, ovarian, brain, acute leukemia, gastric, non-small cell lung, pancreatic, and renal cancer. Further aspects of the invention include methods for treating or reducing the symptoms of xenograft (skin, cell(s), limb, organ or bone marrow transplant) rejection, osteoarthritis, rheumatoid arthritis, cystic fibrosis, complications of diabetes (including diabetic retinopathy and diabetic nephropathy), hepatomegaly, cardiomegaly, stroke (such as acute focal ischemic stroke and global cerebral ischemia), heart failure, septic shock, asthma, and Alzheimer""s disease. Compounds of the invention are also useful as antiviral agents for treating viral infections such as HIV, hepatitis (B) virus (HBV), human papilloma virus (HPV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV). These methods include the step of administering to a patient in need of such treatment, or suffering from such a disease or condition, a pharmaceutically-effective amount of a disclosed compound or pharmaceutical composition thereof.
The invention also features methods of combination therapy, such as a method for treating cancer, wherein the method further includes providing radiation therapy or chemotherapy, for example, with mitotic inhibitors such as a taxane or a vinca alkaloid. Examples of mitotic inhibitors include paclitaxel, docetaxel, vincristine, vinblastine, vinorelbine, and vinflunine. Other therapeutic combinations include a MEK inhibitor of the invention and an anticancer agent such as cisplatin, 5-fluorouracil or 5-fluoro-2-4(1H,3H)-pyrimidinedione (5FU), flutamide, and gemcitabine.
The chemotherapy or radiation therapy may be administered before, concurrently, or after the administration of a disclosed compound according to the needs of the patient.
The invention also includes synthetic intermediates and methods disclosed herein.
Other aspects of the invention are provided in the description, examples, and claims below.
The invention features diaryl amine compounds, pharmaceutical compositions thereof, and methods of using such compounds and compositions.
According to one aspect of the invention, the compounds are MEK inhibitors. MEK inhibition assays include the in vitro cascade assay for inhibitors of MAP kinase pathway described at column 6, line 36 to column 7, line 4 of U.S. Pat. No. 5,525,625 and the in vitro MEK assay at column 7, lines 4-27 of the same patent, the entire disclosure of which is incorporated by reference (see also Examples 1-3 below). A whole cell assay is described below in Example 4.
A. Terms
Certain terms are defined below and by their usage throughout this disclosure.
Alkyl groups include aliphatic (i.e., hydrocarbyl or hydrocarbon radical structures containing hydrogen and carbon atoms) with a free valence. Alkyl groups are understood to include straight chain and branched structures. Examples include methyl, ethyl, propyl, isopropyl, butyl, n-butyl, isobutyl, t-butyl, pentyl, isopentyl, 2,3-dimethylpropyl, hexyl, 2,3-dimethylhexyl, 1,1-dimethylpentyl, heptyl, and octyl. Cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl.
Alkyl groups can be substituted with 1, 2, 3 or more substituents which are independently selected from halo (fluoro, chloro, bromo, or iodo), hydroxy, amino, alkoxy, alkylamino, dialkylamino, cycloalkyl, aryl, aryloxy, arylalkyloxy, heterocyclic radical, and (heterocyclic radical)oxy. Specific examples include fluoromethyl, hydroxyethyl, 2,3-dihydroxyethyl, (2- or 3-furanyl)methyl, cyclopropylmethyl, benzyloxyethyl, (3-pyridinyl)methyl, (2- or 3-furanyl)methyl, (2-thienyl)ethyl, hydroxypropyl, aminocyclohexyl, 2-dimethylaminobutyl, methoxymethyl, N-pyridinylethyl, diethylaminoethyl, and cyclobutylmethyl.
Alkenyl groups are analogous to alkyl groups, but have at least one double bond (two adjacent sp2 carbon atoms). Depending on the placement of a double bond and substituents, if any, the geometry of the double bond may be entgegen (E), or zusammen (Z), cis, or trans. Similarly, alkynyl groups have at least one triple bond (two adjacent sp carbon atoms). Unsaturated alkenyl or alkynyl groups may have one or more double or triple bonds, respectively, or a mixture thereof; like alkyl groups, unsaturated groups may be straight chain or branched, and they may be substituted as described both above for alkyl groups and throughout the disclosure by example. Examples of alkenyls, alkynyls, and substituted forms include cis-2-butenyl, trans-2-butenyl, 3-butynyl, 3-phenyl-2-propynyl, 3-(2xe2x80x2-fluorophenyl)-2-propynyl, 3-methyl(5-phenyl)4-pentynyl, 2-hydroxy-2-propynyl, 2-methyl-2-propynyl, 2-propenyl, 4-hydroxy-3-butynyl, 3-(3-fluorophenyl)-2-propynyl, and 2-methyl-2-propenyl. In formula (I), alkenyl and alkynyl groups can be, for example, C2-4, or C2-8, but are preferably C3-4 or C3-8.
More general forms of substituted hydrocarbon radicals include hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, hydroxycycloalkyl, hydroxyaryl, and corresponding forms for the prefixes amino-, halo- (e.g., fluoro-, chloro-, or bromo-), nitro-, alkyl-, phenyl-, cycloalkyl- and so on, or combinations of substituents. According to formula (I), therefore, substituted alkyls include hydroxyalkyl, aminoalkyl, nitroalkyl, haloalkyl, alkylalkyl (branched alkyls, such as methylpentyl), (cycloalkyl)alkyl, phenylalkyl, alkoxy, alkylaminoalkyl, dialkylaminoalkyl, arylalkyl, aryloxyalkyl, arylalkyloxyalkyl, (heterocyclic radical)alkyl, and (heterocyclic radical)oxyalkyl. R1 thus includes hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, hydroxycycloalkyl, hydroxyphenyl, hydroxy(phenyl)alkyl, (phenyl)hydryoxyalkyl, (C3-8 hydroxylcycloalkyl)-C1-4 alkyl, (C3-8 cycloalkyl)C2-4 hydroxylalkenyl, C3-8 hydroxyheterocyclic radical, (C3-8 heterocyclic radical)C1-4 hydroxyalkyl, aminoalkyl, aminoalkenyl, aminoalkynyl, aminocycloalkyl, aminoaryl, alkylalkenyl, (alkylaryl)alkyl, (haloaryl)alkyl, (hydroxyaryl)alkynyl, and so forth. Similarly, RC includes hydroxyalkyl and aminoaryl, and RD includes hydroxyalkyl, aminoalkyl, and hydroxyalkyl(heterocyclic radical)alkyl and so forth.
Heterocyclic radicals, which include but are not limited to heteroaryls, include: furyl, oxazolyl, isoxazolyl, thiophenyl, thiazolyl, pyrrolyl, imidazolyl, 1,3,4-triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyridazinyl, indolyl, and their nonaromatic counterparts. Further examples of heterocyclic radicals include piperidyl, quinolyl, isothiazolyl, piperidinyl, morpholinyl, piperazinyl, tetrahydrofuryl, tetrahydropyrrolyl, pyrrolidinyl, octahydroindolyl, octahydrobenzothiofuranyl, and octahydrobenzofuranyl.
Selective MEK 1 or MEK 2 inhibitors are those compounds which inhibit the MEK 1 or MEK 2 enzymes, respectively, without substantially inhibiting other enzymes such as MKK3, PKC, Cdk2A, phosphorylase kinase, EGF, and PDGF receptor kinases, and C-src. In general, a selective MEK 1 or MEK 2 inhibitor has an IC50 for MEK 1 or MEK 2 that is at least one-fiftieth ({fraction (1/50)}) that of its IC50 for one of the above-named other enzymes. Preferably, a selective inhibitor has an IC50 that is at least {fraction (1/100)}, more preferably {fraction (1/500)}, and even more preferably {fraction (1/1000)}, {fraction (1/5000)}, or less than that of its IC50 or one or more of the above-named enzymes.
B. Compounds
One aspect of the invention features the disclosed compounds shown in formula (I) in the Summary section.
Embodiments of the invention include compounds wherein: (a) R3 is bromo or chloro; (b) R4 is fluoro; (c) R5 is H; (d) each of R4 and R5 is H; (e) each of R4 and R5 is fluoro; (f) R3 is bromo; (g) R3 is fluoro; (h) R4 is nitro; (i) R5 is H; (j) R6 is chloro; (k) R6 is methyl; (I) R1 is H or C1-4 alkyl, and R2 is H; (m) R1 is (C36 cycloalkyl)methyl; (n) R1 is H; (o) R1 is (CH2)2-4 ORC or (CH2)2-4 NRCRD; (p) R6 is chloro or methyl; (q) R6 is H; or combinations thereof.
Preferably, when R1, RC, or RD is an alkenyl or alkynyl, the double or triple bond, respectively, is not adjacent the point of attachment when the point of attachment is a heteroatom. For example, R1 is preferably prop-2-ynyl, or but-2 or 3-enyl, and less preferably prop-1-ynyl or but-1-enyl.
Examples of compounds of formula (I) include: 4-fluoro-2-(4-iodo-2-methyl-phenylamino)-benzenesulfonic acid; 4-fluoro-N-hydroxy-2-(4-iodo-2-methyl-phenylamino)-benzenesuffonamide; N-cyclopropylmethoxy4-fluoro-2-(4-iodo-2-methyl-phenylamino)-benzenesulfonamide; 3,4-difluoro-2-(4-iodo-2-methyl-phenylamino)-benzenesulfonic acid; 3,4-difluoro-N-hydroxy-2-(4-iodo-2-methyl-phenylamino)-benzenesulfonamide; N-cyclopropylmethoxy-3,4-difluoro-2-(4-iodo-2-methyl-phenylamino)-benzenesulfonamide; 3,4,5-trifluoro-2-(4-iodo-2-methyl-phenylamino)-benzenesulfonic acid; 3,4,5-trifluoro-N-hydroxy-2-(4-iodo-2-methyl-phenylamino)-benzenesulfonamide; N-cyclopropylmethoxy-3,4,5-trifluoro-2-(4-iodo-2-methyl-phenylamino)-benzenesulfonamide; 5-bromo-3,4-difluoro-2-(4-iodo-2-methyl-phenylamino)-benzenesulfonic acid; 5-bromo-3,4-difluoro-N-hydroxy-2-(4-iodo-2-methyl-phenylamino)-benzenesulfonamide; 5-bromo-N-cyclopropylmethoxy-3,4-difluoro-2-(4-iodo-2-methyl-phenylamino)-benzenesulfonamide; 2-(4-iodo-2-methyl-phenylamino)4-nitro-benzenesulfonic N-cyclopropylmethoxy-2-(4-iodo-2-methyl-phenylamino)4-nitro-benzenesulfonamide.
Further examples of compounds include: 2-(2-chloro-4-iodo-phenylamino)4-fluoro-benzenesulfonic acid; 2-(2-chloro-4-iodo-phenylamino)-4-fluoro-N-hydroxy-benzenesulfonamide; 2-(2-chloro-4-iodo-phenylamino)-N-cyclopropylmethoxy-4-fluoro-benzenesulfonamide; 2-(2-chloro-4-iodo-phenylamino)-3,4-difluoro-benzenesulfonic acid; 2-(2-chloro-4-iodo-phenylamino)-3,4-difluoro-N-hydroxy-benzenesulfonamide; 2-(2-chloro-4-iodo-phenylamino)-N-cyclopropylmethoxy-3,4-difluoro-benzenesulfonamide; 2-(2-chloro-4-iodo-phenylamino)-3,4,5-trifluoro-benzenesulfonic acid; 2-(2-chloro-4-iodo-phenylamino)-3,4,5-trifluoro-N-hydroxy-benzenesulfonamide; 2-(2-chloro-4-iodo-phenylamino)-N-cyclopropylmethoxy-3,4,5-trifluoro-benzenesulfonamide; 5-bromo-2-(2-chloro-4-iodo-phenylamino)-3,4-difluoro-benzenesulfonic acid; 5-bromo-2-(2-chloro-4-iodo-phenylamino)-3,4-difluoro-N-hydroxy-benzenesulfonamide; 5-bromo-2-(2-chloro-4-iodo-phenylamino)-N-cyclopropylmethoxy-3,4-difluoro-benzenesulfonamide; 2-(2-chloro-4-iodo-phenylamino)-4-nitro-benzenesulfonic acid; 2-(2-chloro-4-iodo-phenylamino)-N-hydroxy-4-nitro-benzenesulfonamide; or 2-(2-chloro-4-iodo-phenylamino)-N-cyclopropylmethoxy-4-nitro-benzenesulfonamide.
C. Synthesis
The disclosed compounds can be synthesized according to Scheme 1 below. 
One equivalent of appropriately substituted sulfonyl chloride is added to a solution of one equivalent of appropriately substituted hydroxylamine and excess triethylamine in CH2Cl2 or Et2o and stirred for 30 minutes. The triethylamine hydrochloride precipitate is separated by filtration and discarded. If necessary, the product is further purified by chromatography on silica column. The pure 2-fluor hydroxamic or hydroxamate product is then added to a solution of appropriately substituted lithium anilide prepared by adding LDA to the aniline in THF at xe2x88x9278xc2x0 C. After stirring at room temperature for 16 hours, the reaction mixture is poured in to Et2o-HCl. Any precipitated solid is separated by filtration and discarded. The filtrate is concentrated and the resulting crude product is purified on silica column to give the desired target product.
The disclosed compounds can also be made by other synthetic organic methods, as well as automated or combinatorial methods.
D. Uses
The disclosed compositions are useful as both prophylactic and therapeutic treatments for diseases or conditions as provided in the Summary section, as well as diseases or conditions modulated by the MEK cascade. Examples include stroke, heart failure, osteoarthritis, rheumatoid arthritis, organ transplant rejection, and a variety of tumors such as ovarian, lung, pancreatic, brain, prostatic, and colorectal.
1. Dosages
Those skilled in the art will be able to determine, according to known methods, the appropriate dosage for a patient, taking into account factors such as age, weight, general health, the type of pain requiring treatment, and the presence of other medications. In general, an effective amount will be between 0.1 and 1000 mg/kg per day, preferably between 1 and 300 mg/kg body weight, and daily dosages will be between 10 and 5000 mg for an adult subject of normal weight. Commercially available capsules or other formulations (such as liquids and film-coated tablets) of 100 mg, 200 mg, 300 mg, or 400 mg can be administered according to the disclosed methods.
2. Formulations
Dosage unit forms include tablets, capsules, pills, powders, granules, aqueous and nonaqueous oral solutions and suspensions, and parenteral solutions packaged in containers adapted for subdivision into individual doses. Dosage unit forms can also be adapted for various methods of administration, including controlled release formulations, such as subcutaneous implants. Administration methods include oral, rectal, parenteral (intravenous, intramuscular, subcutaneous), intracistemal, intravaginal, intraperitoneal, intravesical, local (drops, powders, ointments, gels, or cream), and by inhalation (a buccal or nasal spray).
Parenteral formulations include pharmaceutically acceptable aqueous or nonaqueous solutions, dispersion, suspensions, emulsions, and sterile powders for the preparation thereof. Examples of carriers include water, ethanol, polyols (propylene glycol, polyethylene glycol), vegetable oils, and injectable organic esters such as ethyl oleate. Fluidity can be maintained by the use of a coating such as lecithin, a surfactant, or maintaining appropriate particle size. Carriers for solid dosage forms include (a) fillers or extenders, (b) binders, (c) humectants, (d) disintegrating agents, (e) solution retarders, (f) absorption acccelerators, (g) adsorbants, (h) lubricants, (i) buffering agents, and (j)propellants.
Compositions may also contain adjuvants such as preserving, wetting, emulsifying, and dispensing agents; antimicrobial agents such as parabens, chlorobutanol, phenol, and sorbic acid; isotonic agents such as a sugar or sodium chloride; absorption-prolonging agents such as aluminum monostearate and gelatin; and absorption-enhancing agents.
3. Related Compounds
The invention provides the disclosed compounds and closely related, pharmaceutically acceptable forms of the disclosed compounds, such as salts, esters, amides, hydrates or solvated forms thereof; masked or protected forms; and racemic mixtures, or enantiomerically or optically pure forms.
Pharmaceutically acceptable salts, esters, and amides include carboxylate salts (e.g., C1-8 alkyl, cycloalkyl, aryl, heteroaryi, or non-aromatic heterocyclic), amino acid addition salts, esters, and amides which are within a reasonable benefit/risk ratio, pharmacologically effective, and suitable for contact with the tissues of patients without undue toxicity, irritation, or allergic response. Representative salts include hydrobromide, hydrochloride, sulfate, bisulfate, nitrate, acetate, oxalate, valerate, oleate, palmitate, stearate, laurate, borate, benzoate, lactate, phosphate, tosylate, citrate, maleate, fumarate, succinate, tartrate, naphthylate, mesylate, glucoheptonate, lactiobionate, and laurylsulfonate. These may include alkali metal and alkali earth cations such as sodium, potassium, calcium, and magnesium, as well as non-toxic ammonium, quaternary ammonium, and amine cations such as tetramethyl ammonium, methylamine, trimethylamine, and ethylamine. See, for example, S. M. Berge, et al., xe2x80x9cPharmaceutical Salts,xe2x80x9d J. Pharm. Sci., 1977, 66:1-19 which is incorporated herein by reference. Representative pharmaceutically acceptable amides of the invention include those derived from ammonia, primary C1-6 alkyl amines and secondary di (C1-6 alkyl) amines. Secondary amines include 5- or 6-membered heterocyclic or heteroaromatic ring moieties containing at least one nitrogen atom and optionally between 1 and 2 additional heteroatoms. Preferred amides are derived from ammonia, C1-3 alkyl primary amines, and di (C1-2 alkyl)amines. Representative pharmaceutically acceptable esters of the invention include C1-7 alkyl, C5-7 cycloalkyl, phenyl, and phenyl(C1-6)alkyl esters. Preferred esters include methyl esters.
The invention also includes disclosed compounds having one or more functional groups (e.g., hydroxyl, amino, or carboxyl) masked by a protecting group. Some of these masked or protected compounds are pharmaceutically acceptable; others will be useful as intermediates. Synthetic intermediates and processes disclosed herein, and minor modifications thereof, are also within the scope of the invention.
Hydroxyl protecting groups include: ethers, esters, and protection for 1,2- and 1,3-diols. The ether protecting groups include: methyl, substituted methyl ethers, substituted ethyl ethers, substituted benzyl ethers, silyl ethers and conversion of silyl ethers to other functional groups.
Substituted Methyl Ethers
Substituted methyl ethers include: methoxymethyl, methylthiomethyl, t-utylthiomethyl, (phenyidimethylsilyl) methoxymethyl, benzyloxymethyl, p-ethoxybenzyloxymethyl, (4-methoxyphenoxy) methyl, guaiacolmethyl, t-butoxymethyl, 4-pentenyloxymethyl, siloxymethyl, 2-methoxyethoxymethyl, 2,2,2-trichloroethoxymethyl, bis(2-chloro- ethoxy)methyl, 2-(trimethylsilyl)ethoxymethyl, tetrahydropyranyl, 3-bromotetrahydro-pyranyl, tetrahydrothiopyranyl, 1-methoxycyclohexyl, 4-methoxytetrahydropyranyl, 4-methoxytetrahydrothiopyranyl, 4-methoxytetrahydrothiopyranyl S,S-dioxido, 1-[(2-chloro-4-methyl)phenyl]-4-methoxypiperidin-4-yl, 1,4-dioxan-2-yl, tetrahydrofuranyl, tetrahydrothiofuranyl, and 2,3,3a,4,5,6,7,7a-octahydro-7,8,8-trimethyl-4,7-ethanobenzofuran-2-yl.
Substituted Ethyl Ethers
Substituted ethyl ethers include: 1-ethoxyethyl, 1-(2,chloroethoxy)ethyl, 1-methyl-1-methoxyethyl, 1-methyl-1-benzyloxyethyl, 1-methyl-1-benzyloxy-2-fluoroethyl, 2,2,2-trichloroethyl, 2-trimethylsilyethyl, 2-(phenylselenyl)ethyl, t-butyl, allyl, p-chlorophenyl, p-methoxyphenyl, 2,4-dinitrophenyl, and benzyl.
Substituted Benzyl Ethers
Substituted benzyl ethers include: p-methoxybenzyl, 3,4-dimethoxybenzyl, o-nitrobenzyl, p-nitrobenzyl, p-halobenzyl, 2,6-dichlorobenzyl, p-cyanobenzyl, p-phenylbenzyl, 2- and 4-picolyl, 3-methyl-2-picolyl N-oxido, diphenylmethyl, p, pxe2x80x2-dinitrobenzhydryl, 5-dibenzosuberyl, triphenylmethyl, xcex1-naphthyldiphenyl-methyl, p-methoxyphenyldiphenylmethyl, di(p-methoxyphenyl)phenylmethyl, tri-(p-methoxyphenyl)methyl, 4-(4xe2x80x2-bromophenacyloxy)phenyldiphenylmethyl, 4,4xe2x80x2,4xe2x80x3-tris(4,5-dichlorophthalimido-phenyl)methyl, 4,4xe2x80x2,4xe2x80x2-tris(levulinoyloxy-phenyl)methyl, 4,4xe2x80x2,4xe2x80x3-tris(benzoyloxy-phenyl)methyl, 3-(imidazol-1-ylmethyl)-bis(4xe2x80x2,4xe2x80x2-dimethoxyphenyl)-methyl, 1,1-bis(4-methoxyphenyl)-1xe2x80x2-pyrenylmethyl, 9-anthryl, 9-(9-phenyl) xanthenyl, 9-(9-phenyl-10-oxo) anthryl, 1,3-benzodithiolan-2-yl, and benzisothiazolyl S,S-dioxido.
Silyl Ethers
Silyl ethers include: trimethylsilyl, triethylsilyl, triisopropylsilyl, dimethylisopropylsilyl, diethylisopropylsilyl, dimethylthexylsilyl, t-butyidimethylsilyl, t-butyidiphenylsilyl, tribenzylsilyl, tri-p-xylylsilyl, triphenylsilyl, diphenylmethylsilyl, and t-butylmethoxy- phenylsilyl.
Esters protecting groups include: esters, carbonates, assisted cleavage, miscellaneous esters, and sulfonates.
Esters
Examples of protective esters include: formate, benzoylformate, acetate, chloroacetate, dichloroacetate, trichloroacetate, trifluoroacetate, methoxyacetate, triphenylmethoxyacetate, phenoxyacetate, p-chlorophenoxyacetate, p-P-phenylacetate, 3-phenylpropionate, 4-oxopentanoate (levulinate), 4,4-(ethylenedithio) pentanoate, pivaloate, adamantoate,crotonate,4-methoxycrotonate, benzoate, p-phenylbenzoate, and 2,4,6-trimethylbenzoate (mesitoate).
Carbonates
Carbonates include: methyl, 9-fluorenylmethyl, ethyl, 2,2,2-trichloroethyl, 2-(trimethylsilyl) ethyl, 2-(phenylsulfonyl) ethyl, 2-(triphenylphosphonio) ethyl, isobutyl, vinyl, allyl, p-nitrophenyl, benzyl, p-methoxybenzyl, 3,4-dimethoxybenzyl, o-nitrobenzyl, p-nitrobenzyl, S-benzyl thiocarbonate, 4-ethoxy-1-naphthyl, and methyl dithiocarbonate.
Assisted Cleavage
Examples of assisted cleavage protecting groups include: 2-iodobenzoate, 4-azido-butyrate, 4-nitro-4-methylpentanoate, o-(dibromomethyl) benzoate, 2-formylbenzene-sulfonate, 2-(methylthiomethoxy) ethyl carbonate, 4-(methylthiomethoxymethyl) benzoate, and 2-(methylthiomethoxymethyl) benzoate.
Miscellaneous Esters
In addition to the above classes, miscellaneous esters include: 2,6-dichloro-4-methylphenoxyacetate, 2,6-dichloro-4-(1,1,3,3-tetramethylbutyl) phenoxyacetate, 2,4-bis(1,1-dimethylpropyl) phenoxyacetate, chlorodiphenylacetate, isobutyrate, monosuccinoate, (E)-2-methyl-2-butenoate (tigloate), o-(methoxycarbonyl) benzoate, p-P-benzoate, xcex1-naphthoate, nitrate, alkyl N,N,Nxe2x80x2,Nxe2x80x2-tetramethyl-phosphorodiamidate, N-phenylcarbamate, borate, dimethylphosphinothioyl, and 2,4-dinitrophenylsulfenate.
Sulfonates
Protective sulfates includes: sulfate, methanesulfonate(mesylate), benzylsulfonate, and tosylate.
The protection for 1,2 and 1,3-diols group includes: cyclic acetals and ketals, cyclic ortho esters, and silyl derivatives.
Cyclic Acetals and Ketals
Cyclic acetals and ketals include: methylene, ethyl idene, 1-t-butylethylidene, 1-phenylethylidene, (4-methoxyphenyl) ethyl idene, 2,2,2-trichloroethylidene, acetonide (isopropylidene), cyclopentylidene, cyclohexylidene, cycloheptylidene, benzylidene, p-methoxybenzylidene, 2,4-dimethoxybenzylidene, 3,4-dimethoxybenzylidene, and 2-nitrobenzylidene.
Cyclic Ortho Esters
Cyclic ortho esters include: methoxymethylene, ethoxymethylene, dimethoxy-methylene, 1-methoxyethylidene, 1-ethoxyethylidine, 1,2-dimethoxyethylidene, xcex1-methoxybenzylidene, 1-(N,N-dimethylamino)ethylidene derivative, xcex1-(N,N-dimethylamino) benzylidene derivative, and 2-oxacyclopentylidene.
Ester protecting groups include: esters, substituted methyl esters, 2-substituted ethyl esters, substituted benzyl esters, silyl esters, activated esters, miscellaneous derivatives, and stannyl esters.
Substituted Methyl Esters
Substituted methyl esters include: 9-fluorenylmethyl, methoxymethyl, methylthiomethyl, tetrahydropyranyl, tetrahydrofuranyl, methoxyethoxymethyl, 2-(trimethylsilyl)ethoxy-methyl, benzyloxymethyl, phenacyl, p-bromophenacyl, xcex1-methylphenacyl, p-methoxyphenacyl, carboxamidomethyl, and N-phthalimidomethyl.
2-Substituted Ethyl Esters
2-Substituted ethyl esters include: 2,2,2-trichloroethyl, 2-haloethyl, 1-chloroalkyl, 2-(trimethylsily)ethyl, 2-methylthioethyl, 1,3-dithianyl-2-methyl, 2(p-nitrophenylsulfenyl)-ethyl, 2-(p-toluenesulfonyl)ethyl, 2-(2xe2x80x2-pyridyl)ethyl, 2-(diphenylphosphino)ethyl, 1-methyl-1-phenylethyl, t-butyl, cyciopentyl, cyclohexyl, allyl, 3-buten-1-yl, 4-(trimethylsily)-2-buten-1-yl, cinnamyl, xcex1-methylcinnamyl, phenyl, p-(methylmercapto)-phenyl, and benzyl.
Substituted Benzyl Esters
Substituted benzyl esters include: triphenylmethyl, diphenylmethyl, bis(o-nitrophenyl)methyl, 9-anthrylmethyl, 2-(9,10-dioxo)anthrylmethyl, 5-dibenzo-suberyl, 1-pyrenylmethyl,2-(trifluoromethyl)-6-chromylmethyl, 2,4,6-trimethyl-benzyl, p-bromobenzyl, o-nitrobenzyl, p-nitrobenzyl, p-methoxybenzyl, 2,6-dimethoxybenzyl, 4-(methylsulfinyl)benzyl, 4-sulfobenzyl, piperonyl, and 4-P-benzyl.
Silyl Esters
Silyl esters include: trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, i-propyidimethylsilyl, phenyidimethylsilyl, and di- t-butylmethylsilyl.
Miscellaneous Derivatives
Miscellaneous derivatives includes: oxazoles, 2-alkyl-1,3-oxazolines, 4-alkyl-5-oxo-1,3-oxazolidines, 5-alkyl4-oxo-1,3-dioxolanes, ortho esters, phenyl group, and pentaaminocobalt(III) complex.
Stannyl Esters
Examples of stannyl esters include: triethylstannyl and tri-n-butylstannyl.
Amides include: N,N -dimethyl, pyrrolidinyl, piperidinyl, 5,6-dihydrophen-anthridinyl, o-nitroanilides, N-7-nitroindolyl, N-8-nitro-1,2,3,4-tetrahydroquinolyl, and p-P-benzenesulfonamides. Hydrazides include: N-phenyl, N,N xe2x80x2-diisopropyl and other dialkyl hydrazides.
Carbamates include: carbamates, substituted ethyl, assisted cleavage, photolytic cleavage, urea-type derivatives, and miscellaneous carbamates.
Carbamates
Carbamates include: methyl and ethyl, 9-fluorenylmethyl, 9-(2-sulfo)fluorenylmethyl, 9-(2,7-dibromo)fluorenylmethyl, 2,7-di-t-butyl-[9-(10,10-dioxo-10,10,10,10-tetrahydro- thioxanthyl)]methyl, and 4-methoxyphenacyl.
Substituted Ethyl
Substituted ethyl protective groups include: 2,2,2-trichloroethyl, 2-trimethylsilylethyl, 2-phenylethyl, 1-(1-adamantyl)-1-methylethyl, 1,1-dimethyl-2-haloethyl, 1,1dimethyl-2,2-dibromoethyl, 1,1-dimethyl-2,2,2-trichloroethyl, 1-methyl-1-(4-biphenylyl)ethyl, 1-(3,5-di-t-butylphenyl)-1-methylethyl, 2-(2xe2x80x2-and 4xe2x80x2-pyridyl)ethyl, 2-(N,N-icyclohexylcarboxamido)- ethyl, t-butyl, 1-adamantyl, vinyl, allyl, 1-isopropylallyl, connamyl, 4-nitrocinnamyl, quinolyl, N-hydroxypiperidinyl, alkyldithio, benzyl, p-methoxybenzyl, p-nitrobenzyl, p-bromobenzyl, p-chlorobenzyl, 2,4dichlorobenzyl, 4-methylsulfinylbenzyl, 9-anthrylmethyl, and diphenylmethyl.
Assisted Cleavage
Protection via assisted cleavage includes: 2-methylthioethyl, 2-methylsulfonylethyl, 2-(p-toluenesulfonyl)ethyl, [2-(1,3-dithianyl)]methyl, 4-methylthiophenyl, 2,4-dimethyl-thiophenyl, 2-phosphonioethyl, 2-triphenylphosphonioisopropyl, 1,1-dimethyl-2cyanoethyl, m-chloro-p-acyloxybenzyl, p-(dihydroxyboryl)benzyl, 5-benzisoxazolyi-methyl, and 2-(trifluoromethyl)-6-chromonylmethyl.
Photolytic Cleavage
Photolytic cleavage methods use groups such as: m-nitrophenyl, 3,5-dimethoxybenzyl, o-nitrobenzyl, 3,4-dimethoxy-6-nitrobenzyl, and phenyl(o-nitrophenyl)methyl.
Urea-Type Derivatives
Examples of of urea-type derivatives include: phenothiazinyl-(10)-carbonyl derivative, Nxe2x80x2-p-toluenesulfonylaminocarbonyl, and Nxe2x80x2-phenylaminothiocarbonyl.
Miscellaneous Carbamates
In addition to the above, miscellaneous carbamates include: t-amyl, S-benzyl thiocarbamate, p-cyanobenzyl, cyclobutyl, cyclohexyl, cyclopentyl, cyclopropylmethyl, p-decyloxy-benzyl, diisopropylmethyl, 2,2-dimethoxy-carbonylvinyl, o-(N,N-dimethyl-carboxamido)-benzyl, 1,1-dimethyl-3(N,N-dimethylcarboxamido)propyl, 1,1-dimethyl-propynyl, di(2-pyridyl)methyl, 2-furanylmethyl, 2-iodoethyl, isobornyl, isobutyl, isonicotinyl, p(pxe2x80x2-methoxyphenyl-azo)benzyl, 1-methylcyclobutyl, 1-methylcyclohexyl, 1-methyl-1-cyclopropyl-methyl, 1-methyl-(3,5-dimethoxyphenyl)ethyl, 1-methyl-1(p-henylazophenyl)-ethyl, 1-methyl-1-phenylethyl, 1-methyl-1-(4-pyridyl)ethyl, phenyl, p-(phenylazo)benzyl, 2,4,6-tri-t-butylphenyl, 4-(trimethylammonium) benzyl, and 2,4,6-trimethylbenzyl.
Amides
Amides includes: N-formyl, N-acetyl, N-chloroacetyl, N-trichloroacetyl, N-trifluoroacetyl, N-phenylacetyl, N-3-phenylpropionyl, N-picolinoyl, N-3-pyridyl-carboxamide, N-benzoylphenylalanyl derivative, N-benzoyl, and N-p-phenylbenzoyl.
Assisted Cleavage
Assisted cleavage groups include: N-o-nitrophenylacetyl, N-o-nitrophenoxyacetyl, N-acetoacetyl, (Nxe2x80x2-dithiobenzyloxycarbonylamino)acetyl, N-3-(p-hydroxphenyl) propionyl, N-3-(o-nitrophenyl)propionyl, N-2-methyl-2-(o-nitrophenoxy)propionyl, N-2-methyl-2-(o-phenylazophenoxy)propionyl, N-4-chlorobutyryl, N-3-methyl-3-nitrobutyryl, N-o-nitrocinnamoyl, N-acetylmethionine derivative, N-o-nitrobenzoyl, N-o-(benzoyloxymethyl)benzoyl, and 4,5-diphenyl-3-oxazolin-2-one.
Cyclic Imide Derivatives
Cyclic imide derivatives include: N-phthalimide, N-dithiasuccinoyl, N-2,3-diphenyl-maleoyl, N-2,5-dimethylpyrrolyl, N-1,1,4,4-tetramethyl-disilylazacyclopentane adduct, 5-substituted 1,3-dimethyl-1,3,5-triaza-cyclohexan-2-one, 5-substituted 1,3-dibenzyl-1,3,5-triazacyclohexan-2-one, and 1-substituted 3,5-dinitro-4-pyridonyl.
Protective groups for xe2x80x94NH include: N-alkyl and N-aryi amines, imine derivatives, enamine derivatives, and N-hetero atom derivatives (such as N-metal, N-N, N-P, N-Si, and N-S), N-sulfenyl, and N-sulfonyl.
N-Alkyl and N-Aryl Amines
N-alkyl and N-aryl amines include: N-methyl, N-allyl, N-[2-(trimethylsilyl)ethoxyl]-methyl, N-3-acetoxypropyl, N-(1-isopropyl-4-nitro-2-oxo-3-pyrrolin-3-yl), quaternary ammonium salts, N-benzyl, N-di(4-methoxyphenyl)methyl, N-5-dibenzosuberyl, N-triphenylmethyl, N-(4-methoxyphenyl)diphenylmethyl, N-9-phenylfluorenyl, N-2,7-dichloro-9-fluorenylmethylene, N-ferrocenylmethyl, and N-2-picolylamine Nxe2x80x2-oxide.
Imine Derivatives
Imine derivatives include: N-1,1-dimethylthiomethylene, N-benzylidene, N-p-methoxybenzylidene, N-diphenylmethylene, N-[(2-pyridyl)mesityl]methylene, N-(Nxe2x80x2,Nxe2x80x2-dimethylaminomethylene), N,Nxe2x80x2-isopropylidene, N-p-nitrobenzylidene, N-salicylidene, N-5-chlorosalicylidene, N-(5-chloro-2-hydroxyphenyl)phenyl-methylene, and N-cyclohexyiidene.
Enamine Derivative
An example of an enamine derivative is N-(5,5-dimethyl-3-oxo-1-cyclohexenyl).
N-Hetero Atom Derivatives
N-metal derivatives include: N-borane derivatives, N-diphenylborinic acid derivative, N-[phenyl(pentacarbonylchromium- or -tungsten)]carbenyl, and N-copper or N-zinc chelate. Examples of N-N derivatives include: N-nitro, N-nitroso, and N-oxide. Examples of N-P derivatives include: N-diphenylphosphinyl, N-dimethylthiophosphiny(, N-diphenylthiophosphinyl, N-dialkyl phosphoryl, N-dibenzyl phosphoryl, and N-diphenyl phosphoryl. Examples of N-sulfenyl derivatives include: N-benzenesulfenyl, N-o-nitrobenzenesulfenyl, N-2,4-dinitrobenzenesulfenyl, N-pentachlorobenzenesulfenyl, N-2-nitro-4-methoxy-benzenesulfenyl, N-triphenylmethylsulfenyl, and N-3-nitropyridinesulfenyl. N-sulfonyl derivatives include: N-p-toluenesulfonyl, N-benzenesulfonyl, N-2,3,6-trimethyl-4-methoxybenzenesulfonyl, N-2,4,6-trimethoxybenzenesulfonyl, N-2,6-dimethyl-4-methoxy-benzenesulfonyl, N-pentamethylbenzenesulfonyl, N-2,3,5,6-tetramethyl-4-methoxybenzene- sulfonyl, N-4-methoxybenzenesulfonyl, N-2,4,6-trimethylbenzenesulfonyl, N-2,6-dimethoxy-4-methylbenzenesulfonyl, N-2,2,5,7,8-pentamethylchroman-6-sulfonyl, N-methanesulfonyl, N-xcex2-trimethylsilyiethanesulfonyl, N-9-anthracenesulfonyl, N-4-(4xe2x80x2,8xe2x80x2-dimethoxynaphthylmethyl)-benzenesulfonyl, N-benzylsulfonyl, N-trifluoromethylsulfonyl, and N-phenacylsulfonyl.
Disclosed compounds which are masked or protected may be prodrugs, compounds metabolized or otherwise transformed in vivo to yield a disclosed compound, e.g., transiently during metabolism. This transformation may be a hydrolysis or oxidation which results from contact with a bodily fluid such as blood, or the action of acids, or liver, gastrointestinal, or other enzymes.
Features of the invention are further described in the examples below.